TORONTO – Vitor Belfort has had three weeks to prepare for one of the top pound-for-pound fighters in the world.

By most estimates, that’s not nearly enough time. Belfort (21-9 MMA, 10-5 UFC), though, is focused on the positives of a short-notice title fight with light-heavyweight champ Jon Jones (16-1 MMA, 10-1 UFC) at UFC 152.

“I’m ready,” he said. “It’s all in my mind. I’m taking advantage of what is positive. Focus on the positive, not what is negative.”

Belfort is a long shot to beat Jones in the headliner of Saturday’s event, which takes place at Air Canada Centre in Toronto. (Main-card fights air on pay-per-view following prelims on FX and Facebook.) Oddsmakers have him a 6-to-1 underdog to unseat Jones, who’s vanquished nearly every top-tier fighter in the 205-pound division in the past 18 months.

Many fans voiced confusion at the announcement of the matchup, which materialized when ex-champ Lyoto Machida turned down a rematch with Jones for the event.

But Belfort, a recent middleweight who returns to light heavyweight for the first time in five years, said that after 17 years in the game, he looks at the situation differently than others. Fighting on short notice is not unfamiliar territory; after all, he fought in early UFC tournaments in which fighters rarely prepared for opponents.

“I come from an era where you just do what you love,” Belfort said. “You cannot be prepared to be a father. You’re a father. You go through the motions and just accept things the way they are.”

Belfort, who initially criticized Jones’ decision to decline Machida but today changed his tune, said he’s studied his long-limbed opponent but hasn’t obsessed on what he’ll encounter inside the cage.

“I’m more focused on what I can do,” he said. “Bottom line is that when you step in that cage, things can turn pretty quick. Sometimes you can study and get surprised. So just enjoy (it). It’s like a soccer player. You’ve just got to go with what God gave you and figure it out at the time.”

Time has been both cruel and kind to the 35-year-old Belfort, who most recently earned a submission win over Anthony Johnson at UFC 142. He’s excelled against opponents in the first round, where he’s earned 15 career wins in five minutes or less. In fights that go the distance, he’s fared poorly, though, and dropped five of six that went 15 minutes.

Faced with the possibility of carrying more bulk for 25 minutes against the 25-year-old Jones, Belfort was confident he could go the distance if needed.

“As far as I know, I’ve got five rounds,” Belfort said. “After five minutes, I’ve got a minute rest. And if the fight goes another five minutes, I have another five-minute round. I’m focusing on the five minutes, so that every minute I’m giving everything I’ve got. It’s a mentality. When your body is tired, your mind carries on.”

At the same time, Belfort said was trying not to think too much during the fight.

“When you think too much, you get tired,” he said.

With three weeks to ready himself, Belfort hasn’t had a tremendous amount of time to think of the challenge ahead.